To simplify the expression cos 72 cos 12 - sin 72 sin 18, we can use the trigonometric identity cos(a-b) = cos a cos b + sin a sin b.
Using this identity, we can rewrite the expression as:
cos(72-12) = cos 60
Since cos 60 = 1/2, the simplified expression is 1/2.
To simplify the expression cos 72 cos 12 - sin 72 sin 18, we can use the trigonometric identity cos(a-b) = cos a cos b + sin a sin b.
Using this identity, we can rewrite the expression as:
cos(72-12) = cos 60
Since cos 60 = 1/2, the simplified expression is 1/2.